A standard packaging system of the wrap-around or tray type employs a blank formed with a bottom panel having side edges formed as fold lines from which project side panels and end edges from which project fastening flaps. The side panels each have opposite end edges formed as fold lines from which project further such flaps and one of the side panels can even have another fold line forming another end edge from which projects a top panel having an opposite end edge formed with another flap. Such a blank is a planar piece of cardboard or the like that is stamped to have the desired outline and to give it the panel- and flap-delimiting fold lines.
A standard method for packaging a group of objects in such a blank is described in German patent document 3,515,248 of A. Ghiretti et al (claiming an Italian priority date of Apr. 27, 1984). Here the blank is delivered horizontal to a loading station where one of the side flaps of the blank, which is horizontal, is folded up into a vertical position and the group of objects is moved perpendicular to this upright side panel onto the base panel and is deposited thereon. Then the other side panel is folded up and the flaps are folded in, and the thus formed package is moved off parallel to the first-erected side panel, that is perpendicular to the infeed direction of the objects being packaged. This change in movement direction represents a substantial impediment to operating rapidly as it requires that the objects be brought at least momentarily to a full stop with the time at a stop wasted as well as the time decelerating to it and accelerating away from it. Furthermore special holders must be provided to retain the flaps against the package once they are folded in and until the glue cures, and this extra equipment elevates the cost of the packaging machine.
In U.S. Pat. No. 4,571,916 of M. Meuwly et al the blanks are fed in synchronously and codirectionally to the objects being packaged. Immediately after the objects are deposited on the base panel and while the blank and objects are still moving the front and rear flaps are bent up through 90.degree. and then the side panels are similarly bent up to the vertical position. Thus the device must be provided with special flap- and panel-manipulating devices which must move along on the conveyor with the package to hold everything in place as the glue sets enough to hold the package shut on its own.
Similarly in U.S. Pat. No. 3,844,088 of D. McDonough et al the finished package is transported away in the same direction as that in which the blank is fed to the loading station. Stationary tools are used to fold the side walls up. A special holding station as in above-cited German 3,515,248 holds the package together as its glue is setting up.
Swiss patent 478,026 of P. Engeler describes a multiple-object packaging system wherein the blank is bent up to be U-shaped, with the erected flaps perpendicular to the transport direction. Two special devices are provided for closing the ends of the package, each comprising two narrow-flap folders followed by two wide-panel folders, the latter being movable along with the conveyed package. The packaging apparatus is therefore fairly long and quite complex.